Transmission system for pod system of marine vessel

ABSTRACT

A transmission system includes a housing, an input shaft, a first bearing, a second bearing, and a hydraulic pump. The housing defines a hydraulic circuit therein. The input shaft rotatably disposed within the housing. The first bearing and the second bearing are mounted on the input shaft, and are spaced apart from each other along a longitudinal axis of the input shaft. The hydraulic pump is disposed between the first bearing and the second bearing. The hydraulic pump is further disposed in fluid communication with the hydraulic circuit.

TECHNICAL FIELD

The present disclosure relates to a transmission system, and more particularly, to a transmission system of a pod system for a marine vessel.

BACKGROUND

Many marine vessels employ transmission systems to transmit power from an engine or a motor to one or more propellers. The transmission systems may have rotating components mounted on shafts, for example, a pump or one or more gears mounted on the shaft. Typically, these shafts may be partially or completely positioned rotatably within a housing with the help of bearings.

For example, U.S. Pat. No. 5,509,863 (hereinafter referred to as '863 patent) discloses a transmission for boats, comprising an input shaft, a reversing mechanism and an output shaft. The reversing mechanism is comprised of two bevel gears freely rotatably mounted on an intermediate shaft and engaged with a bevel gear on the input shaft. The bevel gears each cooperate with an individual clutch respectively, by which one of the bevel gears can be locked to the intermediate shaft. The clutches are compressible by a piston that moves in a cylinder which in turn communicates with a hydraulic pump driven by one of the input and intermediate shafts. The output shaft is driven by a bevel gear having a recess in which one of the clutches is partially received.

In cases such as the '863 patent, rotating components of the hydraulic pump are disposed towards one end of the input shaft while the bearings are disposed towards another end of the shaft. Such an arrangement may affect the stability of the input shaft during operation since the load exerted by the operation of the pump and the support offered by the bearings is concentrated at the ends of the input shaft respectively. Thus, a relative arrangement of the rotating components and the bearings on the input shaft may influence various constructional and operational parameters of the transmission system. Therefore, there is a need to evaluate the arrangement of the rotating components with respect to the bearings on the input shaft and improve an overall stability and performance of the transmission system.

SUMMARY

In one aspect of the present disclosure, a transmission system includes a housing, an input shaft, a first bearing, a second bearing, and a hydraulic pump. The housing defines a hydraulic circuit therein. The input shaft is rotatably disposed within the housing. The first bearing and the second bearing are mounted on the input shaft, and are spaced apart from each other along a longitudinal axis of the input shaft. The hydraulic pump is disposed between the first bearing and the second bearing. Further, the hydraulic pump is in fluid communication with the hydraulic circuit.

In another aspect, the present disclosure provides a pod system for a marine vessel. The pod system includes an engine having an output shaft, and a transmission system. The transmission system includes a housing, an input shaft, a first bearing, a second bearing, and a hydraulic pump. The housing defines a hydraulic circuit therein. The input shaft is coupled to the output shaft of the engine and rotatably disposed within the housing. The first bearing and the second bearing are mounted on the input shaft, and are spaced apart from each other along a longitudinal axis of the input shaft. The hydraulic pump is disposed between the first bearing and the second bearing. Further, the hydraulic pump is in fluid communication with the hydraulic circuit.

Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a rear view of an exemplary marine vessel employing a pod system;

FIG. 2 is a cross-sectional view of a transmission system of the pod system in accordance with an embodiment of the present disclosure; and

FIG. 3 is a cut-away view of an upper housing of the transmission system showing a hydraulic pump.

DETAILED DESCRIPTION

The present disclosure relates to a transmission system, and more particularly, to a transmission system of a pod system for a marine vessel. FIG. 1 shows a side view of a marine vessel 100 employing the pod system 102 in which disclosed embodiments may be implemented. In an embodiment as shown in FIG. 1, the marine vessel 100 is a powered motorboat. The marine vessel 100 includes the pod system 102, and one or more propellers 104. The propellers 104 are typically positioned under water and are configured to drive the marine vessel 100 when powered by the pod system 102.

The pod system 102 includes an engine 106 (shown schematically) having an output shaft 108, and a transmission system 110 coupled to the output shaft 108. Although the present disclosure discloses the engine 106, any type of prime mover commonly known in the art may be used in place of the engine 106 depending on the requirements of a specific application.

The transmission system 110 includes an upper housing 112, a lower housing 114, and an intermediary housing 116 disposed between the upper housing 112 and the lower housing 114. The upper housing 112 and the intermediary housing 116 may be rigidly coupled to each other by means of fasteners commonly known in the art. The lower housing 114 may be rotatably coupled to the intermediary housing 116 such that the lower housing 114 may be rotatable relative to the upper housing 112 and the intermediary housing 116 about a longitudinal axis X-X′ as will be disclosed hereinafter.

FIG. 2 shows a cross-sectional view of the transmission system 110. The transmission system 110 further includes a steering kingpin 126 located on an underside 128 of the intermediary housing 116. The steering kingpin 126 is rotatably supported within the intermediary housing 116 by a pair of needle bearings 130 a, 130 b disposed therebetween. Further, the steering kingpin 126 is rigidly coupled to the lower housing 114. Therefore, the lower housing 114 is configured to rotate in unison with the steering kingpin 126 relative to the intermediary housing 116 and the upper housing 112.

The transmission system 110 further includes a steering assembly 131 associated with the steering kingpin 126. The steering assembly 131 may include a steering motor 133, a steering shaft 135, and one or more gear wheels 137. The steering shaft 135 may be powered by the steering motor 133. The gear wheels 137 may be disposed between the steering shaft 135 and the steering kingpin 126 such that the gear wheels 137 may be configured to transmit steering torque from the steering shaft 135 to the steering kingpin 126. Therefore, the steering kingpin 126 may be configured to rotate relative to the intermediary housing 116 and the upper housing 112 about the longitudinal axis X-X′ (as indicated by curved arrow AA). In this manner, the propellers 104 located on the lower housing 114 may be configured to change direction about the longitudinal axis X-X′ to accomplish steering of the marine vessel 100 (Referring to FIG. 1).

The upper housing 112 includes a first power transmission shaft 118 rotatably supported by bearings 174, 176 disposed therebetween. The bearings 174, 176 disclosed herein may be, for example, needle bearings or tapered roller bearings. Further, the first power transmission shaft 118 is configured to extend beyond the bearing 176 such that the first power transmission shaft 118 passes through a sleeve 139 disposed in an opening 141 of the steering kingpin 126.

Furthermore, the transmission system 110 includes a first clutch pack 166 and a second clutch pack 168 rotatably disposed about the first power transmission shaft 118 by bearings 178, 180 respectively. The bearings 178, 180 disclosed herein may be, for example, needle bearings or tapered roller bearings. The transmission system 110 further includes a pair of clutch pistons 162, 164 i.e. a first clutch piston 162 and a second clutch piston 164 associated with the first clutch pack 166 and the second clutch pack 168 respectively.

The transmission system 110 further includes an input shaft 136 disposed within the upper housing 112. The input shaft 136 extends along a longitudinal axis Y-Y′ which is disposed laterally with respect to the longitudinal axis X-X′ of the first power transmission shaft 118. The input shaft 136 is configured to be driven by the output shaft 108 of the engine 106. The input shaft 136 includes a first gear component 154 mounted at an end 156 thereof.

Further, the transmission system 110 includes a second gear component 158 and a third gear component 160 rigidly mounted on the first power transmission shaft 118. As illustrated in FIG. 2, the first gear component 154, the second gear component 158, and the third gear component 160 may be bevel gears. However, alternative gear types such as worm gears, or crown gears, or other gear arrangements may be used in place of the bevel gears to form the first gear component 154, the second gear component 158, and the third gear component 160.

The transmission system 110 may further include one or more solenoids 151 (not visible in FIG. 1, one solenoid shown in FIG. 3) disposed on the upper housing 112. The solenoids 151 is controlled by an Electronic Control Module (ECM) (not shown), which is configured with one or more executable programs therein. Based on one or more command signals from the ECM, the solenoids 151 may selectively actuate one of the first clutch piston 162 and the second clutch piston 164 such that one of the first clutch pack 166 and the second clutch pack 168 may be actuated. Consequently, one of the second gear component 158 and the third gear component 160 may selectively mesh with the first gear component 154 and configure the first power transmission shaft 118 to rotate in a unitary direction i.e., clockwise direction or anti-clockwise direction, about the longitudinal axis X-X′.

As shown in FIGS. 2-3, the first clutch pack 166 and the second clutch pack 168 are proximally located to each other as compared to the second and third gear components 158, 160. Specifically, the first clutch pack 166 and the second clutch pack 168 are positioned in a pocket 161 defined in the upper housing 112 between the second and third gear components 158, 160. Moreover, the first clutch piston 162 is located between the first clutch pack 166 and the second gear component 158 while the second clutch piston 164 is located between the second clutch pack 168 and the third gear component 160. The specific configuration of the second and third gear components 158, 160 as shown in FIGS. 2-3 allows the first and second clutch packs 166 and 168, and the first and second clutch pistons 162, 164 to be accommodated therein for selective actuation thereof and rotation of the first power transmission shaft 118 about the longitudinal axis X-X′.

The lower housing 114 includes a second power transmission shaft 122 rotatably supported by bearings 124, 132 disposed therebetween. Further, the second power transmission shaft 122 is configured to extend beyond the bearing 124 and rigidly couple with the first power transmission shaft 118 via the sleeve 139. The bearings 174, 176 disposed between the first power transmission shaft 118 and the upper housing 112, and the bearings 124, 132 disposed between the second power transmission shaft 122 and the lower housing 114 are configured to provide support to the first and second power transmission shafts 118, 122 from torque loads during operation of the transmission system 110.

Furthermore, the lower housing 114 includes a third power transmission shaft 143 rotatably supported by bearings 134 a, 134 b disposed therebetween. The second and third power transmission shafts 122, 143 have intermeshing gears 147 a, 147 b mounted thereon. The gears 147 a, 147 b transfer power from the second power transmission shaft 122 to the third power transmission shaft 143 during operation of the transmission system 110 such that the third power transmission shaft 143 may be configured to drive a propeller shaft 149 via a bi-directional gear assembly 145 mounted thereon, for example, a pair of opposing bevel gears mounted on the propeller shaft 149.

Therefore, referring to FIGS. 1 and 2, a structure and functioning of the transmission system 110 may be recapitulated for better understanding of the reader. During operation of the pod system 102, the engine 106 may drive the output shaft 108. The first gear component 154 carried by the input shaft 136 may thus rotate. The solenoids 151 may then actuate one of the first clutch piston 162 and the second clutch piston 164 to actuate the first clutch pack 166 or the second clutch pack 168 respectively. If the first clutch pack 166 is actuated, the second gear component 158 may be configured to engage with the first gear component 154. Similarly, if the second clutch pack 168 is actuated, the third gear component 160 may be configured to engage with the first gear component 154. Engaging the second gear component 158 with the first gear component 154 may rotate the first power transmission shaft 118 in a first direction M, for example, a clockwise direction as shown in FIG. 2. Engaging the third gear component 160 with the first gear component 154 may rotate the first power transmission shaft 118 in a second direction N, for example, a counter clockwise direction as shown in FIG. 2. Consequently, the second power transmission shaft 122 and the third power transmission shaft 143 may rotate in their respective directions of rotation depending on the direction of rotation of the first power transmission shaft 118. Therefore, the propeller shaft 149 may be driven by the third power transmission shaft 143 via the bi-directional gear assembly 145 such that the propellers 104 may be configured to rotate to propel the marine vessel 100.

Referring to FIG. 3, the transmission system 110 further includes a first bearing 138, and a second bearing 140, and a primary hydraulic pump 142. The first bearing 138 and the second bearing 140 are mounted on the input shaft 136. The first and second bearings 138, 140 are spaced apart from each other along a longitudinal axis Y-Y′ of the input shaft 136.

The primary hydraulic pump 142 is disposed about the input shaft 136 and located between the first bearing 138 and the second bearing 140. The primary hydraulic pump 142 includes a first rotor 144 rigidly mounted on the input shaft 136, and a second rotor 146 disposed within the upper housing 112. The second rotor 146 may be configured to co-act with the first rotor 144 to pump a hydraulic fluid therein. In an embodiment, the primary hydraulic pump 142 may be a gerotor pump. The hydraulic fluid disclosed herein may be, for example, oil. For ease in understanding the present disclosure, reference to the hydraulic fluid will be hereinafter made to as “oil”. However, oil disclosed herein is merely exemplary in nature and hence, non-limiting of this disclosure. Any liquid commonly known in the art may be used as the hydraulic fluid of the present disclosure.

The first bearing 138 and the second bearing 140 disposed on either side of the primary hydraulic pump 142 are configured to support the input shaft 136 within the upper housing 112. In an embodiment, the first bearing 138 and the second bearing 140 may be tapered roller bearings such that the first bearing 138 and the second bearing 140 are configured to distribute therebetween, a torque load and/or a bending load in the input shaft 136 during operation of the primary hydraulic pump 142. In an embodiment as shown in FIG. 3, the first bearing 138 and the second bearing 140 are located at a first distance D1 and a second distance D2 from the primary hydraulic pump 142 respectively. The first distance D1 and the second distance D2 disclosed herein may be determined during manufacture of the transmission system 110 while taking into account operating load conditions such as, but not limited to, the torque load and/or bending loads encountered by the input shaft 136 and the primary hydraulic pump 142 during operation of the transmission system 110, or factors such as space constraints present in the transmission system 110.

The primary hydraulic pump 142 is configured to pressurize and supply oil for operation and/or lubrication of various components of the transmission system 110. Turning back to FIG. 2, the upper housing 112, the intermediary housing 116, and the lower housing 114 of the transmission system 110 define a hydraulic circuit 148 disposed in fluid communication with the primary hydraulic pump 142.

In an embodiment as shown in FIG. 2, the hydraulic circuit 148 may include one or more orifices 150, 152 defined in the upper housing 112 of the transmission system 110. The orifices 150, 152 may extend from the primary hydraulic pump 142 to the first and second bearings 138, 140 such that oil may be communicated from the primary hydraulic pump 142 within the orifices 150, 152 to lubricate the first and second bearings 138, 140. The hydraulic circuit 148 may extend to be integral with various components of the transmission system 110 for lubrication and/or actuation of the components as will be disclosed herein.

The hydraulic circuit 148 disclosed herein may extend into the first power transmission shaft 118 to define a first input line 170, and a second input line 172 therein. As shown in FIG. 3, the first input line 170, and the second input line 172 axially extend within the first power transmission shaft 118 to fluidly communicate with the first clutch piston 162 and the second clutch piston 164. The first input line 170 fluidly communicates oil from the primary hydraulic pump 142 to the first clutch piston 162 while the second input line 172 fluidly communicates oil from the primary hydraulic pump 142 to the second clutch piston 164. Therefore, upon selective actuation of the solenoids 151, the primary hydraulic pump 142 may be configured to generate hydraulic pressure of oil within one of the first input line 170 and the second input line 172

INDUSTRIAL APPLICABILITY

Many marine vessels employ transmission systems to transmit power from an engine to one or more propellers. The transmission systems may have rotating components mounted on shafts, for example, a pump or one or more gears mounted on the shaft. Typically, these shafts may be partially or completely positioned rotatably within a housing with the help of bearings. However, in some cases, the rotating components may be located towards one end of the shaft while the bearings are located towards another end of the shaft. An overall arrangement of the rotating components and the bearings on the shafts may influence various constructional and operational parameters of the transmission system.

With reference to the transmission system 110 of the present disclosure, the first bearing 138 and the second bearing 140 are spaced apart from each other along the longitudinal axis Y-Y′ of the input shaft 136. Thereafter, the primary hydraulic pump 142 is disposed between the first bearing 138 and the second bearing 140 with the pre-determined first and second distances D1, D2 respectively.

A person having ordinary skill in the art will acknowledge that during operation of the transmission system 110, the first rotor 144 and the second rotor 146 of the primary hydraulic pump 142 may encounter forces while co-acting relative to each other to pump the oil. These forces may be transmitted to the input shaft 136 rotatably supported within the housing by the first and second bearings 138, 140. A positioning of the first and second bearings 138, 140 at the pre-determined first and second distances D1, D2 from the primary hydraulic pump 142 may distribute operating loads substantially evenly along the input shaft 136 such that the input shaft 136 rotates about the longitudinal axis Y-Y′. Therefore, the relative arrangement of the primary hydraulic pump 142, the first bearing 138, and the second bearing 140 may offer more stability to the input shaft 136 during operation of the primary hydraulic pump 142 and may help to increase a service life of the first and second bearings 138, 140.

Further, the configuration of the second and third gear components 158, 160 with the pocket 161 therebetween, and the subsequent arrangement of the first and second clutch packs 166, 168 within the pocket 161 impart compactness to the transmission system 110. Therefore, the transmission system 110 is rendered with a construction that occupies minimal space while performing the required functions in the pod system 102.

While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machine, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof. 

We claim:
 1. A transmission system comprising: a housing defining a hydraulic circuit therein; an input shaft rotatably disposed within the housing; a first bearing and a second bearing mounted on the input shaft, the first and second bearings being spaced apart from each other along a longitudinal axis of the input shaft; and a hydraulic pump disposed between the first bearing and the second bearing, the hydraulic pump in fluid communication with the hydraulic circuit.
 2. The transmission system of claim 1, wherein the hydraulic pump comprises: a first rotor rigidly mounted on the input shaft; and a second rotor disposed within the housing, wherein the second rotor is configured to co-act with the first rotor to pump a hydraulic fluid.
 3. The transmission system of claim 1, wherein the hydraulic pump is a gerotor pump.
 4. The transmission system of claim 1, wherein the first bearing and the second bearing are tapered roller bearings.
 5. The transmission system of claim 1, wherein the first bearing and the second bearing are located at a first distance and a second distance from the hydraulic pump respectively.
 6. The transmission system of claim 5, wherein the first distance and the second distance are pre-determined based on an operational load of the input shaft and the hydraulic pump.
 7. The transmission system of claim 1, wherein the input shaft further comprises a first gear component mounted at an end thereof.
 8. The transmission system of claim 7 further comprising a first power transmission shaft having a second gear component and a third gear component mounted thereon, the second gear component and the third gear component selectively engaged with the first gear component by a first clutch and a second clutch respectively.
 9. The transmission system of claim 8, wherein the hydraulic pump is configured to actuate the first clutch and the second clutch by hydraulic pressure.
 10. A pod system for a marine vessel, the pod system comprising: an engine having an output shaft; and a transmission system comprising: a housing defining a hydraulic circuit therein; an input shaft coupled to the output shaft of the engine, the input shaft rotatably disposed within the housing; a first bearing and a second bearing mounted on the input shaft, the first and second bearings being spaced apart from each other along a longitudinal axis of the input shaft; and a hydraulic pump disposed between the first bearing and the second bearing, the hydraulic pump in fluid communication with the hydraulic circuit.
 11. The pod system of claim 10, wherein the hydraulic pump comprises: a first rotor rigidly mounted on the input shaft; and a second rotor disposed within the housing, wherein the second rotor is configured to co-act with the first rotor to pump a hydraulic fluid.
 12. The pod system of claim 10, wherein the hydraulic pump is a gerotor pump.
 13. The pod system of claim 10, wherein the first bearing and the second bearing are tapered roller bearings.
 14. The pod system of claim 10, wherein the first bearing and the second bearing are located at a first distance, and a second distance from the hydraulic pump respectively.
 15. The pod system of claim 14, wherein the first distance and the second distance are pre-determined based on an operational load of the input shaft and the hydraulic pump.
 16. The pod system of claim 10, wherein the input shaft further comprises a first gear component mounted at an end thereof.
 17. The pod system of claim 16 further comprising a first power transmission shaft having a second gear component and a third gear component mounted thereon, the second gear component and the third gear component selectively engaged with the first gear component by a first clutch and a second clutch respectively.
 18. The pod system of claim 17, wherein the hydraulic pump is configured to actuate the first clutch and the second clutch by hydraulic pressure. 